Chapter 6The Chemistry of Life

Atoms: The Building Blocks of Life

Both living and non-living things have atomsEverything, living and non, is

made of Atoms.An elements is something you

can break down into a smaller part – even with chemicals.

You can’t see elements with your eyes

Of the naturally occurring elements, only 25 are essential to life.

There are 4 elements that make up 96% of the mass of a human body.

Nitrogen - N

Carbon - C

Hydrogen - H

Oxygen - O

Atom It is the smallest part of an

elementThey are the building blocks

of all matter

As we work fill out your notes Nucleus is the center of an Atom It contains protons (p+) that are

positive It contains neutrons (n) that have no

charge The nucleus has a positive + charge!

The area around the nucleus has small electrons (e-)which are negatively charged.

They stick together like magnets – the positive and negative charges hold it together.

Go back into your notes and compare the pictures of the elements – how are they different????

Energy Levels There are 3 levels

–The first level can only hold 2 electrons

–The second level can no more then 8 (e-)

–The third level can hold no more then 10 (e-)

* Similar to orbits, think of Saturn’s moons

Skip 6.2

Begin with 6.3Life Substances

The Atom Activity

Atoms contain = numbers of electrons and protons so there is no charge

Atom ActivityTime to play with

play doe!

• Take out a piece of paper• Marker/Crayon/Colored

Pencil• Draw Three Rings• Make a Carbon Atom• Pick an element and try a

new one!

Isotopes of an Element

Read page 144 – 147Stop before Chemical

Reactions

Isotope: Atoms of the same element that have different numbers of neutrons.

Compounds and Bonding

A compound is a substance that is composed of atoms of 2 ore more different elements that are chemically combined.

An example is Table SaltNaCl

Sodium and Chlorine

Covalent Bond

These happen in nature because the “compound” is more stable then the individual atom.

Elements prefer to have all of their energy levels full, so they share!

A covalent bond is the force that holds 2 atoms together.

The shared electrons move around each nuclei.

A molecule is a group of atoms held together by covalent bonds.

IonAn ion is a charged particle made

of atoms.Sometimes atoms combine by

first gaining or losing electrons.Ionic Bond: the attractive force

between 2 ions of opposite charge.

Chemical ReactionsThis is when bonds are formed or

broken causing a substance to recombine into something else (another substance)

All chemical reactions that happen inside an organism are that organisms metabolism.

Read Pages 148-149Mixtures – This is when a

combination of substances where the individual substances retain their own properties.

Sand and sugar activity

Solution – is a mixture where 1 or more substances are distributed evenly.

Read Mixtures and SolutionsPg 148-151

What to make Kool Aid!!!

pH – the measure of how acidic or basic a solution is.

Acid is a substance with a pH below 7

Base is a substance with a pH above 7

Acidic pH 2

Acidic pH 4

Neutral pH 7

Base pH of 8

Base pH of 10

pH Lab activity

Skip 6.2Begin with 6.3

Life Substances

Carbon in Organisms

The carbon atom has 4 electrons in its outer energy level that can bond with other elements.

Sometimes elements share electrons to make it more stable.

Carbon can combine with other carbon molecules and other elements.

Bars represent the type of bonds which can be formed.

Single

Double Bond Carbon

Triple Carbon Bond

Three bars to bond the element

When bonding they can form chains, branched chains or rings.

Marshmellows!!!(Don’t eat them – yukkie!)

Use tooth picks and mini marshmellows to make a –Single bond–Double bond–Triple bond

IsomerCarbons are so flexible in

bonding that they can make huge #’s of different structures.Compounds that have the same

chemical formulas but have a different structure are called isomers.

Glucose Fructose

Formula: C6 H12 O6

Glucose Fructose

Formula: C6 H12 O6

Carbon compounds very greatly in size. There can be 1- thousands of carbon atoms in a compound.

These organic compounds are called biomolecules

Proteins are examples of biomolecules.

PolymerCells build these biomolecules by

bonding small molecules together. These chains of molecules are called polymers.

Condensation is a chemical reaction that can form polymers.

Many polymers are formed by condensation (when water is added) and can be broken by hydrolysis (when water is taken away).

*Movie Clip

Carbohydrate

Carbohydrates are used in humans and animals to provide energy for the body.

We get this by eating food.A “carb” is a biomolecule which is

made of carbon, hydrogen and oxygen.

Monosaccharide

Examples are simple sugars:

FructoseGlucose

When glucose and fructose are lined together by condensation sucrose is formed which is a disaccharide (table sugar)

The largest carb molecules are called polysaccharides –polymers made of many monosaccharide sub units.

Examples this are:

Starches

Glycogen

Stored in the liver – form of energy

Cellulose

Found in plants

Lipids Are fats, oils,

waxes and steroids Large

biomolecules that are made of carbon, hydrogen with a little bit of oxygen

Lipids are insoluble in water –example is olive oil, bacon grease. Saturated – each carbon is

bonded to the other carbons by a single bondUnsaturated – there is a double

bond presentCells use lipids to store energy

Proteins (Meat)A protein is a large complex

polymer made of carbon, hydrogen, oxygen, and nitrogen.Read page 160- Structures of

proteins 163.

Amino acids - Basic building blocks for proteins (muscle)

Peptide Bond – The covalent bond formed between the amino

acids.

Enzyme – a protein that changes the rate of a chemical reaction

Nucleic Acid – a complex biomolecule that stores cellular information in a form of a code

Nucleotide –subunits of nucleic acid formed from a simple sugar, phosphate group and a nitrogenous base